638235779 has 2 divisors, whose sum is σ = 638235780. Its totient is φ = 638235778.

The previous prime is 638235737. The next prime is 638235797. The reversal of 638235779 is 977532836.

It is a happy number.

Together with next prime (638235797) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 638235779 - 2¹² = 638231683 is a prime.

It is a super-3 number, since 3×638235779³ (a number of 27 digits) contains 333 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (638235179) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319117889 + 319117890.

It is an arithmetic number, because the mean of its divisors is an integer number (319117890).

Almost surely, 2^638235779 is an apocalyptic number.

638235779 is a deficient number, since it is larger than the sum of its proper divisors (1).

638235779 is an equidigital number, since it uses as much as digits as its factorization.

638235779 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1905120, while the sum is 50.

The square root of 638235779 is about 25263.3287394991. The cubic root of 638235779 is about 860.9812933471.

The spelling of 638235779 in words is "six hundred thirty-eight million, two hundred thirty-five thousand, seven hundred seventy-nine".